Air current operated land mine

ABSTRACT

A land mine to be detonated by strong vertical air currents produced by a decending helicopter. The mine includes a housing having a screened opening in one of the housing surfaces. A rotatable fan is located in the opening and a detonator is operated by the fan to ignite a high explosive in the mine housing. The fan is recessed from the housing surface to prevent horizontal wind reaction with the blades of the fan.

Elnited States Patent Hall [151 macaw [451 Aug. 1,1972

AIR CURRENT OPERATED LAND MINE Inventor: Marvin J. Hall, Huntsville, Ala.

Assignee: The United States of America as represented by the Secretary of the Army Filed: April 29, 1970 Appl. No.: 26,802

US. Cl ..102/8, 102/70.2 G Int. Cl ..F42b 23/26 Field of Search 102/8-10, 16-18,

[56] References Cited UNITED STATES PATENTS 1,226,732 5/1917 White l02/70.2 G 2,926,611 3/1960 Hinman, Jr. l02/70.2 G 3,170,403 2/1965 Heilprin ..102/70.2 G

Primary Examiner-Samuel W. Engle 5 7] ABSTRACT A land mine to be detonated by strong vertical air currents produced by a decending helicopter. The mine includes a housing having a screened opening in one of the housing surfaces. A rotatable fan is located in the opening and a detonator is operated by the fan to ignite a high explosive in the mine housing. The fan is recessed from the housing surface to prevent horizontal wind reaction with the blades of the fan.

3 Claims, 1 Drawing Figure Pmmimuc 1 m2 Marvin J. Hall,

INVENTOR AIR CURRENT OPERATED LAND MINE BACKGROUND OF THE INVENTION This invention is in the field of land mines. Land mines adapted to be detonated by vertical air currents are unknown. In the past helicopters could easily avoid conventional land mines by hovering above the ground surface.

SUMMARY OF THE INVENTION This invention relates to a mechanism whereby a high explosive mine is detonated by strong vertical air currents produced by a decending helicopter. The air currents activate a fan which in turn either mechanically or electrically detonates the mine.

The invention may be better understood from the following detailed description taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single figure shown in the drawing is a perspective view of the land mine.

PREFERRED EMBODIMENT OF THE INVENTION Reference numeral I indicates generally the land mine including a housing 3 having a top surface 5 provided with an opening 7. A venturi type fan 9, i.e., requires little energy to start turning, is aligned in the opening and recessed from surface 5 to prevent horizontal wind reaction on the fan. Screen 11 placed above the fan serves to disperse heavy rain drops and thus prevents the possibility of starting the fan to rotate. The fan is connected to a detonator 13 by a shaft 15 that has a magnetized portion 15. The detonation initiator can be electrical or mechanical but in either case the initiator would be activated by vertical air currents. Reference numeral 17 generally indicates one type of electrical initiator and includes coils 19 of conductive wire mounted in close proximity to the magnetized portion of the shaft for coaction therewith to perform the function of an electrical generator. Coils 19 are connected to a transistor 21 and when sufficient current is generated in the coils the transistor becomes conductive. A battery 23 supplies the current for operating a detonator bridgewire 25.

When fan 9 is rotated to a critical speed, based on the force of a vertical down draft of a helicopter, sufficient electrical current is generated in coils 19 to cause the transistor to conduct and allows current from battery 23 to activate detonator 15 and explode a high explosive 27. A mechanical means (not shown) could include a spring wound by the fan to a pre-determined tension at which the spring would release a percussion pin causing the mine to explode.

While the housing shown is of rectangular cross section, it could be made of different shapes to resist overturning by surface winds or force of the down drafts.

I Claim:

1. A land mine disposed for operation by vertical air currents comprising: a housing having at least a top surface thereon provided with an opening; a screen covering said opening; a rotatable fan alinged with said opening and recessed from said surface to prevent horizontal wind reaction on said fan; a shaft connected with said fan for rotation therewith' a detonation initiator connected to said shaft for activation thereby; and a high explosive disposed in said housing that is ignited when said vertical air currents cause rotation of said fan and operation of said detonation initiator.

2. A land mine as in claim 1 wherein said detonation initiator is disposed to be supplied by an electrical source and includes a magnetized portion of said shaft and electrical coils in proximity to said magnetized portion for generating an electric current.

3. A land mine as in claim 2 wherein said electrical initiator further includes a transistor that is caused to become conductive by said current and a bridgewire series connected for energizing said detonator. 

1. A land mine disposed for operation by vertical air currents comprising: a housing having at least a top surface thereon provided with an opening; a screen covering said opening; a rotatable fan alinged with said opening and recessed from said surface to prevent horizontal wind reaction on said fan; a shaft connected with said fan for rotation therewith; a detonation initiator connected to said shaft for activation thereby; and a high explosive disposed in Said housing that is ignited when said vertical air currents cause rotation of said fan and operation of said detonation initiator.
 2. A land mine as in claim 1 wherein said detonation initiator is disposed to be supplied by an electrical source and includes a magnetized portion of said shaft and electrical coils in proximity to said magnetized portion for generating an electric current.
 3. A land mine as in claim 2 wherein said electrical initiator further includes a transistor that is caused to become conductive by said current and a bridgewire series connected for energizing said detonator. 